Filter device

ABSTRACT

The invention relates to a filter device, in particular for fluids contaminated with water admixtures, such as diesel oil, comprising a filter housing ( 1 ), which can hold at least one filter element ( 9 ), the fiber medium ( 11 ) of which separates an untreated side ( 13 ) from a treated side ( 19 ) during the filtration process in the filter housing ( 1 ), wherein a water collecting unit ( 5 ) is provided, which holds separated water on the treated side, wherein said filter device is characterized in that water that has been separated on the untreated side ( 13 ) also reaches the collecting unit ( 5 ) and in that mutually separated collecting chambers ( 61, 67 ) are present in the collecting unit ( 5 ) for the water that is discharged both at the treated side ( 19 ) and at the untreated side ( 13 ).

The invention relates to a filter device, in particular for fluids contaminated with water admixtures, such as diesel oil, comprising a filter housing, which can hold at least one filter element, the filter medium of which separates an untreated side from a treated side during the filtration process in the filter housing, wherein a water collecting unit is provided, which holds separated water on the treated side.

Filter devices of the kind, as mentioned above, are known in the prior art. They are used, for example, in fuel systems for combustion engines to protect sensitive components, particularly injection systems, against impairment due to water fractions that are carried along in the fuel. The separation of the water fractions, which are carried along in the fuel, can be achieved herein by a coagulation process that causes the formation of water droplets on the filter medium that can then flow off from a separating chamber, which is formed on the filter element, to the water collecting unit.

Based on this prior art, it is the object of the present invention to provide a filter device that is characterized by a comparatively higher level of efficiency in terms of water separation.

According to the invention, this object is achieved by a filter device with all the characteristics of Claim 1.

According to the characterizing portion of Claim 1, an essential special aspect of the invention is the fact that the water collecting unit has collecting chambers formed therein for water that is discharged from the treated side as well as for water that is discharged from the untreated side.

In contrast to the prior art, this means that, in addition to utilizing the coalescence effect by means of which droplet formation occurs, when the filter medium penetrates on the treated side of the system, water that is separated on the untreated side is also routed into the allocated collecting chamber of the collecting unit. The water separation on the untreated side is primarily achieved by means of separating relatively large water drops based on a gravitational effect; however, utilizing a coalescence effect, additional droplet formation can also be achieved on the untreated side of the filter medium, in particular, when the filter medium is coated with a coalescing medium on the untreated side thereof. Due to the separation on the untreated side, it is not necessary for the entire water load in the fuel to completely penetrate the filter medium; instead, only small and the tiniest water drops pass through the filter medium, coalesce and are separated into the collecting chamber on the clean side that is separate from the collecting chamber on the untreated side. Advantageously, it is therefore possible to operate the filter device according to the invention with fuel having a higher water load and without detriment to the effect, for example, due to an excess saturation of the filter medium.

The two collecting chambers are preferably separated from each other in a fluid-proof manner.

In especially advantageous embodiments, fluid can flow through the filter element from the outer, untreated side, that is adjacent to the side wall of the filter housing, toward the inner filter cavity that constitutes the treated side, and from which the separated water is discharged into the first collecting chamber of the collecting unit.

Especially preferred embodiments provide a separating means that forms a separating element between the bottom end of the main part of the housing that receives the filter element, as well as between the first and second collecting chambers of the water collecting unit.

In embodiments of this kind, the configuration can be particularly advantageously selected such that the separating means includes a central opening that is aligned with the axis of the filter cavity of the filter element for discharging the water that is separated on the treated side into the collecting chamber that is centrally located in the collecting unit, as well as at least one passageway that is radially offset relative to the opening for discharging water that is separated on the untreated side toward the second collecting chamber, which surrounds the first collecting chamber.

For the connection between the untreated side and the allocated collecting chamber, it is possible to provide a gap between the interior wall of the housing and the base-side end region of the filter element, preferably in form of a circumferential annular gap, through which the water is discharged from the untreated side to the collecting chamber that can be allocated thereto.

The arrangement is particularly advantageously selected such that the bottom end of the filter medium or of the base-side end region of the filter element directed toward the collecting unit is framed by an end cap that can be fastened to an element receptacle of the filter housing, which includes the central opening for the water that is discharged from the treated side and forms the separating means, together with a wall part that extends between the central opening and the side wall of the housing, and inside which the openings for the water discharge from the untreated side are formed.

It is especially advantageous to select the configuration in such a manner that the element receptacle for receiving a central pipe connection of the end cap that continues the filter cavity includes a central receptacle connection, and the bottom edge of which that is directed toward the collecting unit is constituted by a bowl-shaped base part of the housing that is in a sealed connection with the top end edge of the first collecting chamber, and which is constituted by a hollow cylinder that is centrally disposed in the base part and closed on the base side.

In preferred embodiments, the wall part of the element receptacle that includes the openings for the water that is discharged from the untreated side is adjacent to a downward protruding annular body of the housing that forms the connection between the main part of the housing and the base part, and the side wall of which is connected to the annular body by a sealing element, thus closing, together with the same, the second collecting chamber on the untreated side, which surrounds the internally located first collecting chamber.

A discharge screw is preferably disposed on the base side of each collecting chamber, and it is especially advantageous when the arrangement is selected such that the base part includes a wall part that allows at least for the visual detection of at least the filling state of the outer, second collecting chamber. The base part is advantageously formed in one piece, for example, of a plastic material that offers sufficient transparency.

To provide for visibility in cases when the water volume of the inner collecting chamber on the treated side is surrounded in large part by a water quantity that is discharged on the untreated side, giving the operator the possibility to discharge water quantities that are separated on the treated and untreated sides, and in as far as possible free of any diesel oil located there-above, the apparatus is advantageously configured such that the discharge screw of the inner, first collecting chamber is disposed on a viewer tube that extends downward from the base of the first collecting chamber to create a visually usable monitoring path.

The invention will be illustrated in further detail below using the embodiment that is depicted in the drawings.

Shown are as follows:

FIG. 1 is a longitudinal section of a fuel filter device according to the prior art that is equipped with a water separation device;

FIG. 2 is a longitudinal section of an embodiment of the filter device according to the invention, drawn as a slightly schematically simplified representation; and

FIG. 3 is a partially enlarged longitudinal section of the area designated as III in FIG. 2.

The invention will be explained in further detail below using the example of a fuel filter that is provided in a (not shown) fuel supply system of a combustion engine for cleaning diesel oil that is contaminated with certain water admixtures. The invention is equally suited for other types of fluids.

The device includes a filter housing 1 with a main part 3 in the shape of a hollow cylinder, as well as a base part that follows at the bottom side thereof. On the top end, there is a screwed connection of a housing lid 7 with the main part 3; said housing lid is removable for the installation and removal of a filter element 9. This is an intermediate space between the outer side of the filter medium 11, which is constituted of a filter mat, of the filter element 9 that is received by the housing 1, and the interior wall of housing 1 that constitutes the untreated side 13 during the filtration process. The fuel that must be cleaned can be supplied to the untreated side 13 through an inlet opening 15 and flows through the filter element 9 from the outside to the inside toward an interior filter cavity 17, which constitutes the treated side 19 during the filtration process.

End caps 21 and 23 are provided on the ends of filter elements in a customary manner; they form framings for the filter medium 11 and a fluid-permeable support tube 25 that is located adjacent to the inner side thereof. A hydrophobic screen 26 is disposed at a radial distance relative to the support tube 25 that surrounds the inner filter cavity 17 in the manner of a pipe. Such fuel filters use a filter medium 11 to achieve a separation of water that has a coagulating effect on the water being carried along by the fuel, thus causing the water to precipitate as droplets that are left behind in the intermediate space between the support tube 25 and the hydrophobic screen 26 and then sink downward, because the screen 26 is impermeable to coagulated water drops. The intermediate space thus constitutes a water separating chamber 27 into which the separated water sinks, all the way down to the end cap 23.

The filter element 9 is mounted to an element receptacle 29, which is fixed on the housing, by this bottom end cap 23, and the element receptacle is located above the base part that forms a water collecting chamber 31, from which separated water can be discharged via a water outlet 33. For the interaction with the element receptacle 29, the end cap 23 includes, corresponding to the prior art, a central pipe connection 35 as an opening for the cleaned fuel that exits on the treated side 19, meaning the inner filter cavity 17, and reaches a fuel outlet 37 disposed in the element receptacle 29, and from there the outer side of the housing 1. For the discharge of the separated water located in the separating chamber 27, the end cap 23 contains a water opening 39 that surrounds the pipe connection 35, that is open toward the separating chamber 27 and through which the separated water reaches the water collecting chamber 31 immediately along the outer side of the element receptacle 29. The corresponding flow behavior is illustrated in FIG. 1 by the flow arrows indicating the flow directions; of those, arrow 41 indicates the fuel inflow to the untreated side 13, arrow 43 indicates the flow of the cleaned diesel oil, and arrow 45 indicates the water flow. For the purpose of sealing the untreated side 13, which is located on the outer side of the filter element 9 in relation to the base-side water collecting chamber 31, a sealing apparatus is disposed on the outer circumference of the end cap 23 in the form of a sealing ring 47 that provides sealing action against the inner side of the filter housing. The end cap 23 thus constitutes a separating means that separates the main part 3 of the housing 1 from the base part disposed there-below, which constitutes the water collecting chamber 31.

FIG. 2 shows the embodiment of the filter device according to the invention that is to be described here; the inlet opening (15 in FIG. 1) for the fuel inlet to the untreated side 13 of the housing 1 is presently not shown. The internal structure of the filter element 9 is also not shown, as it can correspond to the prior art, as depicted in FIG. 1. As in FIG. 1, for a decontaminated fuel discharge from the treated side 19, meaning the internal filter cavity 17, a fuel outlet 37 is provided, disposed in the element receptacle 29, leading to the outer side of the housing 1.

While the end cap 23 of the filter element 9 in the prior art constitutes the separating means between the housing main part 3 and the collecting unit (base part) disposed there-below on the radially externally located edge with a sealing element 47 that rests against the housing wall, in the embodiment as shown in FIG. 2, a gap 18 is disposed between the outside edge of the end cap 23 and the housing wall 53, by which the untreated side 13 continues downward in the direction of the element receptacle 29. Water that is separated in the untreated side 13 is thus discharged in the direction of the base part, as illustrated by the arrow 45. Not only does the element receptacle 29 constitute, by the receptacle pipe 49 thereof that protrudes upward, the seat for the central pipe connection 35, which protrudes from the end cap 23 of the filter element 9 and is received in a sealing manner by means of sealing rings 57 in the receiving pipe connection 49, it also forms the separating means between the untreated side 13 and the treated side 19, and it is thus disposed in the base part between a first collecting chamber 61 on the treated side and a second collecting chamber 67 on the untreated side. Inside the same, the first collecting chamber 61 is formed by a hollow cylinder 59 that is closed at the base side and open to the top. The end edge of this top opening of the first collecting chamber 61 is connected to the bottom end edge 65 of the receptacle pipe connection 49 of the element receptacle 29 via a sealing ring 63. This way, the first water collecting chamber 61, which is a component of the treated side 19 of the system, is sealed in a fluid-proof manner in relation to the space surrounding the same within the base part. This part constitutes the second water collecting chamber 67.

As a component of the separating means, the element receptacle 29 includes a wall part 51 that extends between the receiving pipe connection 49 and the housing wall 53. This wall part 51 includes passageways 55 that open, next to the hollow cylinder 59 of the first collecting chamber 61 in the second collecting chamber 67 surrounding the same, and through which the water that is separated on the untreated side is discharged, such that the second collecting chamber 67 therein constitutes a component of the untreated side 13 in this regard. To achieve a sealing action of the second collecting chamber 67 relative to the side wall 53 of the housing 1, the base part that is formed in a bowl-type shape slips past the top edge region thereof, over an annular body 69 that extends downward from the wall part 51 that includes the passageways 55, wherein a sealing element 71 is inserted between steps on the annular body 69 and the wall of the base part in order to seal off the second collecting chamber 67 to the outside.

The base part can be shaped in one piece from a material that is transparent to light, at least to such an extent that a visual detection of the filling level is possible. While the outside-lying second collecting chamber 67 is visually accessible, monitoring the filling level of the inside-lying first collecting chamber 61 can be rendered more difficult, or even completely impossible, when the outer collecting chamber 67 is filled to a corresponding level. To remedy this situation, the base-side discharge means 73 and 75, respectively, that are provided for both collecting chambers 61 and 67, respectively, are disposed at different heights, wherein, as shown in the drawing, the discharge means 73 is disposed away from the base of the first collecting chamber 61, offset downward by means of pipe connection 77. Correspondingly, the pipe connection 77 acts as a viewer tube for discharge processes allowing for the discharge of water from the first water collecting chamber 61 to such a level that virtually no diesel oil that is located there-above is discharged, because it is possible to visually monitor the discharge process. The same applies, correspondingly, for discharge processes from the second collecting chamber 67, the filling level of which is easily monitored visually. 

1. A Filter device, in particular for fluids contaminated with water admixtures, such as diesel oil, comprising a filter housing (1), which can hold at least one filter element (9), the filter medium (11) of which separates an untreated side (13) from a treated side (19) during the filtration process in the filter housing (1), wherein a water collecting unit (5) is provided, which holds separated water on the treated side, characterized in that water that has been separated on the untreated side (13) also reaches the collecting unit (5), and in that mutually separated collecting chambers (61,67) are present in the collecting unit (5) for the water that is discharged on the treated side (19) and on the untreated side (13).
 2. The filter device according to claim 1, characterized in that the collecting chambers (61,67) are separated from each other in a fluid-proof manner.
 3. The filter device according to claim 1, characterized in that primarily a coalescing means is used to separate water on the treated side (19), and that primarily a gravitational effect is used to separate water on the untreated side (13).
 4. The filter device according to claim 1, characterized in that the filter element (9) can, during the filtration process, accommodate flow-through from the outer, untreated side (13), that is adjacent to the side wall (53) of the filter housing (1), toward the inner filter cavity (17) that constitutes the treated side (19), and from which, the water that is separated on the treated side is discharged into the first collecting chamber (61) of the collecting unit (5).
 5. The filter device according to claim 1, characterized in that a separating unit (29, 51) is provided that constitutes a separating element separating the main part (3) of the housing (1) that receives the bottom end of the filter element (9), as well as between the first and the second collecting chambers (61, 67) of the water collecting unit (5).
 6. The filter device according to claim 1, characterized in that the separating means (29, 51) includes a central opening (39) that is aligned with the axis (16) of the filter cavity (17) of the filter element (9) for discharging the water that is separated on the treated side into the collecting chamber (61), which is centrally disposed in the collecting unit (5), as well as at least one passageway (55), which is radially offset relative to the opening (39), for discharging water that is separated on the untreated side into the second collecting chamber (67), which surrounds the first collecting chamber (61).
 7. The filter device according to claim 1, characterized in that at least one gap opening, preferably shaped as a circumferential annular gap (18), is provided between the inner wall of the housing (1) and the base-side end region of the filter element (9), and by which the water flows from the untreated side (13) into the collecting chamber (67) that can be allocated thereto.
 8. The filter device according to claim 1, characterized in that the bottom end of the filter medium (11) that is directed toward the collecting unit (5), or the end region of the filter element (9) on the base side, is framed by an end cap (23) that can be fastened to an element receptacle (29) of the filter housing (1), which includes the central opening (39) for water that flows from the treated side (19) and that constitutes the separating unit (29, 51), together with the wall part (51) that extends between the central opening (39) and the side wall (53) of the housing (1), in which the passageways (55) are formed for the discharge of water from the untreated side (13).
 9. The filter device according to claim 1, characterized in that the element receptacle (29) for receiving a central pipe connection (35) of the end cap (23), which continues the filter cavity (17), includes a central receiving pipe connection (49), the bottom end edge (65) of which, which is directed toward the collecting unit, that is constituted of a bowl-shaped base part of the housing (1), has a sealed connection with the top end edge of the first collecting chamber (61), which is constituted of a centrally disposed hollow cylinder (59) that is closed on the base side.
 10. The filter device according to claim 1, characterized in that the wall part (51) of the element receptacle (29), which includes the passageways (55) for water that is discharged from the untreated side (13), is adjacent to a annular body (69) of the housing (1) that protrudes downward, constituting the connection between the main part (3) of the housing (1) and the base part, and the side wall of which is connected to the annular body (69) by a sealing element (71), closing off the second collecting chamber (67), which encloses the first collecting chamber (61) disposed therein, together with said second collecting chamber.
 11. The filter device according to claim 1, characterized in that a discharge screw (73, 75) is disposed on the base side of each collecting chamber (61, 67).
 12. The filter device according to claim 1, characterized in that the base part includes at least one wall part that allows for the visual detection of at least the filling level of the outer, second collecting chamber (67).
 13. The filter device according to claim 1, characterized in that the discharge screw (73) of the inner, first collecting chamber (61) is disposed on a viewer tube (77) that extends downward from the base of the first collecting chamber (61) for creating a visually usable monitoring path.
 14. The filter device according to claim 1, characterized in that the base part, including the viewer tube (77), are made of a material that is, at least to a limited degree, transparent for light.
 15. The filter device according to claim 1, characterized in that the collecting unit (5), with the individual collecting chambers (61, 67) thereof, is made in one piece. 